(CNN) -- [Breaking news alert, 7:12 p.m. ET]
The U.S. intelligence community is leaning toward a theory that "those in the cockpit" -- the pilots of Malaysia Airlines Flight 370 -- were deliberately responsible for whatever happened to the commercial jetliner that vanished, a U.S. official with direct knowledge of the latest thinking told CNN on Saturday.
The official, speaking on condition of anonymity, says the Malaysian government had wanted a reason to search the homes of the pilot and co-pilot for several days, but it was only in the last 24 to 36 hours the technical analysis of the collected radar and satellite data gave Malaysian officials sufficient reason to inspect those residences.
[Original story published at 5:55 p.m. ET]
Malaysian jet's disappearance a 'deliberate' action, PM says
The Malaysian Prime Minister stopped short of calling the mysterious disappearance of Flight 370 a hijacking, but said Saturday the jet veered off course due to apparent deliberate action taken by someone aboard.
With new clues indicating the Malaysia Airlines jet may have flown for more than seven hours after last contact with the pilots, the search entered a second agonizing week.
Authorities refocused their investigation on the crew and passengers and widened their targeted area to a large swath of Asian geography. The arc of possible places the plane could have flown bends as far north as Kazakhstan and south to the vast, empty waters of the Indian Ocean.
The Boeing 777-200ER passenger jetliner disappeared March 8, en route from the Malaysian capital Kuala Lumpur to Beijing, China.
Military radar showed the jetliner flew in a westerly direction back over the Malaysian peninsula before turning northwest toward the Bay of Bengal or southwest into the Indian Ocean, said Prime Minister Najib Razak.
"Evidence is consistent with someone acting deliberately from inside the plane," he said, officially confirming the plane's disappearance was not caused by an accident.
"Despite media reports that the plane was hijacked, we are investigating all major possibilities on what caused MH370 to deviate," he said.
Military radar showed that the plane flew in a westerly direction back over the Malaysian peninsula before turning northwest toward the Bay of Bengal or southwest into the Indian Ocean, Najib said.
The new satellite information, Najib said, leads authorities to be fairly certain that someone disabled the Aircraft Communications Addressing and Reporting System, or ACARS, just before the aircraft reached the east coast of peninsular Malaysia.
"Shortly afterward, near the border between Malaysian and Vietnamese air traffic control," Najib said, "the aircraft's transponder was switched off."
ACARS is the system that routinely transmits information like turbulence and fuel load back to the airline and the transponder is a radio transmitter in the cockpit used to communicate with air traffic controllers.
The last voice communication from the cockpit a week ago were these words: "All right, good night."
They were uttered at the Vietnam air traffic control border, after ACARS and the transponder were shut off, Razak said. That suggests the incident on the plane began sooner than initially thought.
But some have questioned the Prime Minister's account, given the dearth of information available.
In the days since the flight disappeared, the Malaysian government has been under intense scrutiny for its handling of the investigation. The government has been criticized by some U.S. officials for not sharing information or accepting more offers of help.
Shortly after Najib delivered his remarks, China demanded Malaysia provide more information on the investigation.
"Today is the 8th day of the missing MH370, and the plane is still yet to be found," said a statement from the foreign ministry. "Time is life."
Pilot's home searched
After Najib spoke with reporters, a source close to the investigation told CNN that Malaysian police had searched the home of pilot Zaharie Ahmad Shah, 53. Shah lives in a gated community in Shah Alam, outside Kuala Lumpur.
Police made no comment about their activities at the home of co-pilot, Fariq Ab Hamid, 27. Two vans exited the home carrying small bags, similar to shopping bags, but it was unclear whether the bags were taken from the home.
Transcript: Malaysian Prime Minister's statement on Flight 370
Najib made it clear that in light of the latest developments, authorities have refocused their investigation into the crew and passengers on board. Undoubtedly, they will scour through the flight manifest and look further to see whether anyone on board had flight training or connections to suspect groups.
Kazakhstan to Indian Ocean
As the focus of the investigation shifted, so, too, has the focus of the search.
Information from international and Malaysian officials indicate that the jet may have flown for more than seven hours after the last contact with the pilots.
Flight 370 took off from Kuala Lumpur at 12:41 a.m. The last satellite communication from the plane occurred at 8:11 a.m., Najib said, well past the scheduled arrival time in Beijing.
That last communication, Najib said, was in one of two possible traffic corridors shown on a map released to the press. A northern arc stretches from the border of Kazakhstan and Turkmenistan to northern Thailand, and a southern arc spans from Indonesia to the southern Indian Ocean.
"Due to the type of satellite data, we are unable to confirm the precise location of the plane when it last made contact with the satellite," Najib said.
Because the northern parts of the traffic corridor include some tightly guarded airspace over India, Pakistan, and even some U.S. installations in Afghanistan, U.S. authorities believe it more likely the aircraft crashed into waters outside of the reach of radar south of India, one U.S. official told CNN. If it had flown farther north, it's likely it would have been detected by radar.
Najib said authorities were ending search operations in the South China Sea and reassessing the deployment of assets.
"This new satellite information has a significant impact on the nature and scope of the search operation," he said.
Investigators, he said, have confirmed by looking at the raw satellite data that the plane in question was the Malaysia Airlines jet.
The same conclusion was reached by the U.S. Federal Aviation Administration, the U.S. National Transportation Safety Board, the British Air Accidents Investigation Branch and the Malaysian authorities, all of whom were working separately with the same data, he said.
Families hold onto hope
For the families and loved ones of the 239 people aboard Flight 370, Saturday was Day 8 of anguish. Some found comfort that there is no evidence the plane made impact.
The father of one passenger watched Najib's news conference at a Beijing hotel. He said he hoped the plane was hijacked because that gave him reason to think his son was alive.
"I hope they are alive no matter how small the chance is," he said.
The search that began last weekend now involves 14 countries, 43 ships and 58 aircraft, Najib said, and that the relevant foreign embassies have been given access to the new information.
Malaysia's Foreign Ministry will brief the governments that had passengers aboard the plane and will brief the relatives of the passengers and crew.
China is sending technical experts to join the investigation, and two Chinese search vessels headed for the Strait of Malacca, according to the state-run Xinhua news agency.
After wrapping a search that lasted close to three days in the Gulf of Thailand, the Haikou missile destroyer is due to reach the Strait of Malacca late Saturday. Another vessel, the Yongxingdao, equipped with underwater robots and rescue boats, is set to join the search in the Strait of Malacca after concluding its search in the eastern part of the Gulf of Thailand.
Flight 370 was carrying 154 Chinese passengers.
Plane was taking 'strange path'
Hours before Najib's announcement, U.S. officials told CNN the flight had made drastic changes in altitude and direction after disappearing from civilian radar.
The more U.S. officials learn about the flight, "the more difficult to write off" the idea that some type of human intervention was involved, an official familiar with the investigation said.
CNN has learned that a classified analysis of electronic and satellite data suggests the flight may have crashed in the Bay of Bengal or elsewhere in the Indian Ocean.
Taken together, the data point toward a possible scenario in which someone may have taken control of the plane for some unknown purpose.
The jetliner was flying "a strange path," a U.S. official said on condition of anonymity. The details of the radar readings were first reported by The New York Times on Friday.
Malaysian military radar showed the plane climbing to 45,000 feet -- which is above its approved altitude limit -- soon after disappearing from civilian radar screens and then dropping to 23,000 feet before climbing again, the official said.
Najib noted that theories and conspiracy theories on what happened abound.
"There has been intense speculation," Najib said. "We understand the desperate need for information on behalf of the families and those watching around the world. But we have a responsibility to the investigation and the families to only release information that has been corroborated."
Posted by: Lindsay Sax